It comes and goes, though I doubt we will ever be more active here than this place was after the 1.3 launch. Most of the time, the old people are tired of this place, and the new people are the ones who keep it going, though the trickle of new people coming in that actually stick around has been slowing.

I joined this forum in 2015, but I'm active like literally everyday. So I don't think that some old people are inactive. Like most of the new members don't even visit this forum often after logging in.

as a GM, don't get bogged down in the rules. Sometimes it's better to wing it a bit to make it flow better and be funner for the players (which is the primary goal afterall). 90% of the time the players won't be able to tell between you exactly following the campaign/rulebook and you making stuff up.

For a group of entirely first timers I would very much encourage running a pre-made adventure path instead of trying to jump right into a homebrew thing. Additionally I find it helps to end every session by asking for feedback from the players; what did they like, what didn't they like, did they get enough of a spotlight, etc.